刃裏もれ改良ペースト塩ビグレードの開発

摘要

Polyvinyl chloride paste sol, when subjected to the coating process run at high speed, may cause cumulative adhesion of the sol onto the reverse side of the blade in the coating machine, referred to as "spitting." We investigated how to suppress this phenomenon, with particular regard to the normal stress difference of the PVC paste sol used. We found that, within the high-shear rate region, normal stress difference PVC sol tended to increase with regard to the increase in the shear rate. Normal stress differences varied depending on the resin and increase in the normal stress difference led to occur spitting in a short time. Further, average particle diameter and particle size distribution of the PVC paste sol affected spitting characteristics. Based on those findings, we investigated the optimization of the particle size distribution of PVC paste that governed the compatibility of material characteristic requirements with anti-spitting performance, and successfully developed a wall paper-grade PVC paste. The new grade thus developed shows improvement in spitting suppression, an increase in processing speed, and a decrease in the amount of diluent required. Consequently, it is expected to contribute to both TVOC reduction and cost reduction.%ペースト塩ビゾルの刃裏もれ特性の向上検討に際rnし、ゾルの法線応力差に着目した。これまで行なわれrnなかった高せん断領域でのゾルの法線応力差の測定をrn行い、これが刃裏もれ現象と相関することを明らかにrnした。また、法線応力差がレジンの粒子径分布の影響rnを受けることがわかった。